1. Field of the Invention
The invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having a thin thickness and light weight.
2. Discussion of the Related Art
With the rapid development of information technology, flat panel display (FPD) devices, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), electroluminescent display (ELD) devices and field emission display (FED) devices, have been developed and have replaced cathode ray tubes (CRTs) because of their thin thickness, light weight, and low power consumption.
Among these devices, liquid crystal display (LCD) devices widely used for monitors of notebook computers, monitors of personal computers and as displays for televisions because the LCD devices are excellent at displaying moving images and have a high contrast ratio.
LCD devices are not self-luminescent and require an additional light source. By disposing a backlight unit at the rear side of a liquid crystal panel to emit light into the liquid crystal panel, discernible images can be displayed. Backlight units may include cold cathode fluorescent lamps (CCFLs), external electrode fluorescent lamps (EEFLs) or light-emitting diodes (LEDs) as a light source.
Recently, the LEDs are widely used as a light source for a display device because of their small sizes, low power consumption and high reliability.
FIG. 1 is a cross-sectional view illustrating a liquid crystal display (LCD) module including LEDs as a light source according to the related art.
In FIG. 1, the related art LCD module includes a liquid crystal panel 10, a backlight unit 20, a support main 30, a top cover 40 and a cover bottom 50. The liquid crystal panel 10 displays images and includes first and second substrates 12 and 14 attached with a liquid crystal layer (not shown) interposed therebetween.
The backlight unit 20 is disposed at a rear side of the liquid crystal panel 10. The backlight unit 20 includes an LED assembly 29, a reflection sheet 25, a light guide plate 23 and a plurality of optical sheets 21. The LED assembly 29 is disposed at an edge of at least one side of the support main 30 along a length direction. The reflection sheet 25 is disposed over the cover bottom 50 and is white- or silver-colored. The light guide plate 23 is disposed over the reflection sheet 25. The plurality of optical sheets 21 are disposed over the light guide plate 23.
More particularly, the LED assembly 29 is disposed at a side of the light guide plate 23. The LED assembly 29 includes a plurality of LEDs 29a and a flexible printed circuit board (FPCB) 29b on which the LEDs 29a are planted.
Side surfaces of the liquid crystal panel 10 and the backlight unit 20 are surrounded by the support main 30 having a rectangular frame shape. The top cover 40 covers edges of a front surface of t he liquid crystal panel 10, and the cover bottom 50 covers a rear surface of the backlight unit 20. The top cover 40 and the cover bottom 50 are combined with the support main 30 to thereby constitute one-united body.
Lights emitted from the LEDs 29a are incident on the side surface of the light guide plate 23 and are refracted toward the liquid crystal panel 10. The lights are changed to have uniform brightness and high qualities through the plurality of optical sheets 21 and are provided to the liquid crystal panel 10. Accordingly, the liquid crystal panel 10 displays images.
Meanwhile, the LCD device is widely used for monitors of desktop computers or wall mounted televisions as well as portable computers. Studies for an LCD device with remarkably reduced weight and size while having a large display area have been actively made.
However, since the LCD device includes lots of elements, it is limited to reduce a thickness and a weight of an LCD device. In addition, it is easy that unnecessary electric charges such as static electricity flow into the LCD device, and this affects the arrangement of liquid crystal molecules (not shown) in the liquid crystal panel 10 and do damage to a normal operation. Accordingly, image qualities are lowered.